This invention relates to a forced air control valve for use in an air system which delivers air from an air pump to the exhaust system to an internal combustion engine. The air control valve may be shifted to divert air to atmosphere from the exhaust system.
Reference is made to prior U.S. Pat. No. 3,520,320 dated July 14, 1970 entitled "By-pass and Pressure Relief Valve" as an example of prior art in which a forced air control valve is provided to divert air from the exhaust system to the atmosphere particularly during deceleration to minimize or eliminate backfire conditions. The control valve in U.S. Pat. No. 3,520,320 is a diaphragm actuated valve that is spring biased in one direction with the manifold vacuum overcoming the biasing means to move the valve member to a position for venting the flow of air to atmosphere. The air is vented to atmosphere only for a predetermined period of time which is controlled by a calibrated air bleed through the diaphragm. Thus, after the air has been vented to atmosphere for such a predetermined time, the diaphragm then moves the valve to a position in which air is again supplied to the exhaust system.